There are 52 playing cards in four suits. If three cards are required to be adjacent (regardless of color), how many cards should be touched at least?

To simplify this problem, suppose there is only one set of 13 cards:

2，3，4，5，6，7，8，9， 10

In the worst case, a card in the middle of a set of two cards is separated, such as:

2,3 | 5,6 | 8,9 | j, Q|A or 2 | 4,5 | 7,8 8| 10/0, J|K, a, etc.

According to the pigeon hole principle, if you touch 10 cards, there must be 3 adjacent points. Then arrange the four colors into a matrix:

2, 3, 4, 5, 6, 7, 8, 9, 10, j, q, k, a red.

2, 3, 4, 5, 6, 7, 8, 9, 10, j, q, k, a black.

2, 3, 4, 5, 6, 7, 8, 9, 10, j, q, k, a grass

2, 3, 4, 5, 6, 7, 8, 9, 10, j, q, k and a

According to the simplified segmentation method, it is obtained that 4 1 sheet is needed, and there must be 3 adjacent points regardless of the color.

If we turn this problem into a mathematical classification, I believe there are more mathematical solutions to this problem.